1. Field of the Invention
The present invention is directed to the design of integrated circuits. More specifically, but without limitation thereto, the present invention is directed to estimating crosstalk between an aggressor net and a victim net in an integrated circuit design.
2. Description of Related Art
In the design of integrated circuits using deep sub-micron technology, crosstalk analysis plays a critical role in predicting the performance of the final product. The accuracy of the crosstalk analysis is determined by the accuracy of the model used to estimate crosstalk propagated from an aggressor net to a victim net in an integrated circuit design. A preferred model for estimating crosstalk is the variable voltage output resistance (VVOR) model. The VVOR model accounts for the non-linear variation in the output resistance vs. voltage measured at the output of a driver cell. In a typical crosstalk model, a crosstalk waveform is calculated using an initial estimate of VVOR at the output of the victim net driver cell. An average crosstalk voltage is calculated from the crosstalk waveform, and the average crosstalk voltage is used to find a new value of VVOR from the measured VVOR curve. If the new value of VVOR is not equal to the initial VVOR estimate within a desired tolerance, then the initial estimate is replaced with the new value. The crosstalk waveform and the average crosstalk voltage are recalculated, and the corresponding value of VVOR is compared to the previous value until the value of VVOR has converged to the desired tolerance.